The invention relates to a force transducer with an electromehanical transducer element for fitting in force plates. It relates also to a force plate or measuring platform equipped with a transducer of this kind.
Force plates are employed especially in metal-cutting technology and biomechanics for measuring forces in one or more directions, also for measuring torques as well. When measuring metal-cutting operations for example, they enable the machining operation to be analyzed dynamically, so that the machining parameters can be optimized. In biomechanics, the sequence of movements involved in walking for example can be analyzed, enabling mechanical defects to be diagnosed. Measuring platforms or force plates of this kind are described for example in DE--A 19 52 522, DE--A 33 13 960 and CH--A 595 623.
The force plates used typically in biomechanics consist mostly of a cover plate or base frame with force transducers arranged between them. Measuring platforms for metal-cutting technology consist mostly of two force introduction plates (a base and a cover plate), again with force transducers arranged between them. The force transducers are sealed or protected only imperfectly if at all against extraneous influences. Moreover they constitute a separate intermediate layer, involving commensurate loss of rigidity in the measuring system.
It is therefore the object of the invention to create a force transducer of the kind described above in which the previous disadvantages already mentioned are eliminated, making possible a tightly sealed force plate design which virtually excludes extraneous influences.
The invention achieves this aim by providing the force transducer adjacent at least a first axial end with an essentially radial mounting flange having a larger outside diameter than the outside diameter adjacent a second axial end, for fixing it tightly sealed in a mounting hole of the base plate of the measuring platform. The differently dimensioned axial ends of the transducer allow simple mounting in the base plate, in that the transducer can be inserted through the mounting hole till its mounting flange fits in the mounting hole. The mounting flange is then joined tightly to the mounting hole of the base plate bY suitable means, such as welding, brazing, soldering or cementing. In this way, the force transducer becomes an integral part of the force plate, essentially shielded against outside influences. Preferably the force transducer has signal leads radially extending at a point located between the axial ends. When fitting the force transducer in the mounting hole of the base plate, these signal leads are made to lie in a suitable recess provided in it, so that they too are shielded from extraneous influences.
Consequently a force plate according to the invention is distinguished by having at least one force transducer of the kind described integrated in it, having signal leads inside the base plate running out.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.